Supply system for telephone-circuits.



J. L. HALL. SUPPLY SYSTEM FOR TELEPHONE CIRCUITS.

APPLICATION FILED JUNE e, 1906.

925,093, Patented June 15, 1909.

Witnesses: lnvevtor:

John L. Hall. by

outrun srar is l A tlZh-TT carton.

JOHN L. HALL, OF SOHENEOTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SUPPLY SYSTEM FOR TE LE PHONE-CIBCUI'IS.-

Specification of Letters Patent.

Patented June 15, 1909.

T all whom it may concern:

Be it known that I, Jenn L. HALL, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Supply Systems for ".lelephoneCircuits, of which the following is a specification.

My invention relates to current-supply systems for telephone circuits, and its object is to provide a novel and ellicient system for this purpose.

in attempting to employ directcurrent dynalilo-electric machines heretofore, it has been found that the small pulsations in the current as the dill'erent commutator segments pass under the brush is sutticient to interfere with the satisfactory operation of the telephone, unless auxiliary means, such as storage batteries or large choke-coils are employed to prevent the pulsations. Both batteries and choke-coils are costly and in- 'ehicicnt.

A dynamo-electricmachine having a uniform homopolar field gives a perfectly uniform current without any pulsations what- Lever, and consequently may be connected directly to a telephone circuit without the use of any auxiliary devices for maintaining an even current flow. Sacha machine may furthermore he connected so as to be driven electrically as a rotary converter from. a supply circuit for this purpose.

The machine may be formed with a number of armature conductors connected in series so that the armature terminals may be connected to a source of comparatively high voltage, such, for instance, as a lighting circuit, while the leads for the telephone circuit may be connected to intermediate points Gfthe armature circuit across only v a portion of the conductors. In this way, the machine acts as a. rotarytransformer, reducing the volta e to the desired amount and smoothing out t e current so as to remove small pulsations received from the lighting circui My invention will best be understood by reference to the accompanying drawing, which shows somewhat diagrammatically a telephone supply system arranged in accordance with my invention.

In the drawing'A represents the field magnet of a dynamo-electric machine which is arranged to give a uniform homopolar field.

a a represent the field coils which extend circnmt'erentially around the shaft, and which may be excited from any suitable source of constant current, as by connecting them across the armature terminals or to a separate source of current.

B represents the revolving armature, which carries a plurality of armature conductors I). These conductors are connected at opposite ends to collector rings 0, and by means of brushes c and cross-connections between the brushes the armature conductors may all be connected in series. The terminals of the armature circuit are shown connected through-a switch to theline-wires D representing a suitable source of current, such, for instance, as a lighting circuit.

The line-wires E of a telephone circuit are connected through a switch 0 to intermediate points in the armature circuit across only a portion of the armature conductors. The voltage delivered to the telephone circuit E consequently bears the same relation to the voltage of the lighting circuit D as the number of conductors across which the telephone circuit is t-(Hilltt'l'td h ors to the total number of armature conductors in series. The machine thus acts as a voltage transformer. and it further acts to smooth out the small pulsations in the current received from the lighting mains and to deliver-a cuit.

Telephonic devices it are indicated (liagramnmtically as connected across the telephone circuit- E, and bells or call-magnets (i are shown connected between the line-wires E and ground. The arniatures of these magnets may be polarized in a manner t're; quently employed fmypartydines, so that by sending a pulsating current through either line-wire to ground one hell only may be operated. this pulsating current two make-and-break contact devices H aremounted on the shaft of the unipolar generator and. the central point of the armature circuit of the generator is grounded. By closing the proper switch 71. either line-wire may be connected 'to either device H, which acts to couuect the line-wire intermittently to one armature terminal. Thus a pulsating current of either perfectly even current to the telephone Oil For the purpose of deli\'ering.

t om! vither line-wire EGl' caihnzagnct at, the no tightlng (iii'flll d rive-11 uni-form anopoimi for 910511 a co tim'cof a pin t of and. coiiccting dcvh ton i om. ti placing; saiii conduit t sci-1w; a cup} iy circuit connect-ed, to the toyi v nnnais tin. annatmic circuit a load circuit conncctcn across, :2 (action only of said cm and tcionhxn a connected to s magnetization thcroofl iincavires connected to Fain line-wires, polarized can-magnets connected hotwccn said iincwvircs and earth, 11 Jan: for connccti either terminal of said nmchinc intclgn'iittchtiy to eithcr lino-Wire, and an earth connection to thc'ccntcr of the az'n'iataic c'r nit of the machine.

5. in combinatiol v 1 dyrmmo-cicctrit: machinc haying a nni'foi'm homopolai' field tnagnch moans for producing a constant magnetization then-20f, tine-wires connected to said. mat tcl QilODQS conncctcci across said iinc-wucs, pohvmzcd aU-magncts conncctmi between said lino-wires and cal-tin an carth connawion to tho center of thannaiini'c (SiiCUi, of thc machine, two mahcmndiJi'Bllhi dcviccs on tho shaft 01" the machine unmet-ted to the 'i'ca ncctivc terminals of tho armature circuit, and matches for connect- 1 the lnachina and. means for connecting t ai'niatn tcrn'nnai muol'mlttcntly to atc machine, tcicphoncs connected across. 

